Perchlorate in Milk Already Considered in California's Public Health Goal

Monday, June 21, 2004
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Extremely low levels of perchlorate that may be present in some milk are far below levels that could cause any kind of adverse health effect. Reports of perchlorate being detected in milk are in fact not new as evidenced by the State of California's Public Health Goal (PHG) for perchlorate, established in January 2004, which specifically accounts for exposure to the compound through farm products and cow's milk.

PHG Already Considers Milk:

    1. On page 84 of its PHG for perchlorate in drinking water, which is already overly protective, California's Office of Environmental Health Hazard Assessment (OEHHA) states, "RSC = relative source contribution; a value of 60 percent is used for pregnant women to account for exposure to perchlorate in food such as farm produce and cow's milk." This means OEHHA assumed 60 percent of perchlorate exposure could come from drinking water, and 40 percent could come from milk and food.

    No Heath Effects:

    2. Perchlorate in milk acts the same way as perchlorate in drinking water and credible science has shown no evidence that low levels of perchlorate in drinking water are capable of having any effect on the health of adults, children or fetuses. A summary of these studies includes:

    • Tellez, et al. (2004). This study examined pregnant women and babies from three cities in Chile, where perchlorate levels range from non-detect to 110 parts per billion (ppb) in water. Preliminary analysis of the findings has found no impacts on the women or on fetal development.
    • Greer, et al. (2002). This study found no impact of perchlorate at levels below 180 - 220 ppb.
    • University of California, Irvine Urban Water Research Center report "Perchlorate and Drinking Water: A Science and Policy Review (2004)." While this report stopped short of saying what levels of perchlorate should be allowable in water, it did state "health benefits for reductions of exposure in concentrations in drinking water below 100 µg/L are difficult to demonstrate." (100 µg/L is equal to 100 ppb)

    3. The first measurable effects of perchlorate on the human body (which Greer shows don't begin until about 200 ppb) are themselves harmless. The body reacts to these levels of perchlorate the same way it reacts to a serving of broccoli or Brussels sprouts, which produce the same effect on the body as perchlorate. According to the research, only at very high levels of perchlorate (at least 17,000 ppb) - consumed daily - could there be even a risk of any adverse effect.

The health effects of perchlorate are currently under review by a panel of the National Academy of Sciences, which is expected to issue its report later this year. California, like Massachusetts and the U.S. Environmental Protection Agency, has stated it will consider the findings of the panel before deciding whether to move forward in setting a standard for perchlorate in drinking water.